1. Field of the Invention
The present invention relates to a flying toy, and more particularly to a vertically ascending, wing shaped airplane.
2. Description of the Prior Art
Toys have long been an integral and important part of childhood. Playing with toys offers a simple pleasure that is shared by young and old alike. Besides providing hours of enjoyment, toys also challenge children to exercise and develop their imagination. A growing number of toys are being designed to fulfill an educational purpose as well by teaching children various social and scientific concepts and notions in a fun, noncompetitive environment. Spinning tops, building blocks, toy automobiles and airplanes can teach a child a wide variety of physical concepts, and such toys are increasingly being used as part of classroom instruction to teach relatively advanced concepts involving aerodynamics, fluid dynamics, materials science, and application of the basic laws of physics.
Toy airplanes in particular have been extremely popular both for their entertainment and educational value, and a large number of designs have been developed over the years. The first designs were simplistic gliders formed from folded sheets of paper that were thrown by the user into the air to glide back down to the ground. An early example of such a glider is disclosed in U.S. Des. Pat. No. 55,102 to Van Shrum, wherein the single drawing depicts a flying toy contoured in a shape reminiscent of a butterfly with tapered wings and rearwardly projecting elements symmetrically disposed about a central longitudinal axis. Another design for a glider is disclosed in U.S. Pat. No. 2,410,627, wherein a flat body formed to resemble the head and body of a bird is attached to a sheet of paper shaped to resemble the wings and tail of a bird to form a glider. The glider is thrown into the air and is described as being able to glide through the air for a comparatively considerable distance. U.S. Pat. No. 3,540,149 to Lowe discloses a very similar glider that includes a pair of wings shaped like bird's wings, a fuselage shaped like a bird's head, body and tail, and a weighted strip mounted to the fuselage. A second weighted strip reinforces the wing structure, holds the wings at a predetermined dihedral angle, and further adds weight near the center of gravity of the glider.
U.S. Pat. No. 3,909,976 to Kirk also discloses a glider toy that incorporates a weight member that is located forward of the glider's center of gravity. The glider is contoured with a outwardly convex leading edge and two long, trailing leg sections that can bent to various angles relative to the body. The flight path of the glider can thus be altered by bending these leg sections, or by throwing the glider into the air with a twisting motion to cause it to flip from side to side during flight. This glider is designed primarily to be used indoors by being thrown in the manner of a dart. U.S. Pat. No. 4,388,777 discloses a toy sailplane suitable for outdoor use which incorporates a single piece, swept back wing with a weight suspended from its lower surface. The wing is shaped to respond to changes in wind by alternately soaring or gliding, and is described as being able to fly for an extended period of time. The position of the suspended weight is adjustable and can thus be used to vary the center of gravity of the toy and thereby change the angle of attack of the wing.
The sophistication of models such as those described above grew as lighter and stronger materials became available, and with the advent of the now ubiquitous rubber-band, powered flight became possible. A simple and straightforward method of harnessing the resilient power of a rubber-band is to hook a glider to one end of a rubber band, stretch the rubber band, then release it in slingshot fashion to launch the glider with a higher launch velocity than typically achieved by manually throwing the glider into the air. This is the concept behind the glider disclosed in U.S. Pat. No. 3,768,198 to Fields, wherein one or more sheets of foldable material are shaped into wing and body sections and clamped together with a bent piece of wire which extends downwardly into a hook configuration to engage a rubber band for launching the plane. In a much more sophisticated design, Schwarz discloses in U.S. Pat. No. 4,863,413 a bird shaped toy glider including a body with a laminated head structure incorporating a metal weight and a collapsible wing structure mounted on the body. In operation, the wings are collapsed and the glider is launched in slingshot fashion by a rubber band to climb until its speed drops below a predetermined speed, allowing a rubber band mounted to the wing structure to expand the wing into a deployed position to glide the toy throughout its descent.
The devices described above and others like them are enjoyable to watch and can be employed to teach students many fundamentals of flight dynamics. In addition, they are all relatively inexpensive to produce. However, none of these designs addresses one of the most exciting developments in flight of the past few decades, the vertically ascending helicopter. A helicopter is a relatively complex device, and consequently can teach a different set of principles to students attempting to model its operation. To many, the flight of a helicopter is more entertaining to watch than a glider, and thus a number of toy designs have been developed that mimic a helicopter's mode of operation. U.S. Pat. No. 1,287,779 to Springer, for instance, discloses a device comprising a wing mounted to a frame equipped with a rubber band powered propeller. A second rubber band is mounted to a second frame that slidingly engages the first frame and causes the entire device to jump in the air when stretched and released, at which time the propeller begins to rotate and causes the device to fly over a horizontal flight path of some distance. In U.S. Pat. No. 2,308,916, Halligan discloses a flying toy that ascends and descends vertically and includes a body with a vertical mast upon which a horizontal propeller is rotatably mounted. Two vertically positioned propellers are rotatably mounted on opposite sides of the horizontal propeller and are powered by a rubber band connected between them. As the vertical propellers begin to turn, they cause the horizontal propeller to turn as well, thereby creating vertical thrust to lift the toy off the ground and ascend vertically. While very amusing and entertaining, neither of these devices fully and correctly mimics the actual operating principles of a helicopter and are therefore of limited educational use.
Nemeth in U.S. Pat. No. 2,439,143 discloses a toy helicopter equipped with a rubber band powered propeller that causes it to ascend vertically and counter rotating vanes to stabilize the device during ascent. The body of the device supports a mast upon which the propeller and the vanes are mounted. A slightly different approach is taken by Horak in U.S. Pat. No. 2,138,168, wherein a toy rocket is disclosed to include a conical body with an upwardly projecting hollow mast supporting a stationary propeller and a rotating propeller powered by a rubber band extending within the mast. The two propellers have blades with opposite pitch and thus during flight rotate in opposite directions to lift the toy along a stable vertical path. The conical body helps guide the rocket, and at the apex of the flight path causes it to rotate towards the ground so as to land on the hub of the rotating propeller. In yet another variation, U.S. Pat. No. 3,479,764 to Meyer discloses a toy consisting primarily of a hollow shaft containing a rubber band within that is attached to counter-rotating propellers mounted to opposite ends of the shaft, and a device for locking one of the propellers in place while the other propeller is being turned to twist the rubber band drive and thereby store energy to be released during flight.
These devices are relatively similar to each other and describe toys that both ascend and descend vertically, thus creating the potential for damaging the device and injuring the users or bystanders. This problem was solved partially by M. Dandrieux as early as 1879 with a device comprising a thin flexible wing attached to, and symmetrical about, a longitudinal member with a propeller rotatably mounted to its forward end and a rubber band attached between a rear end and the propeller at the forward end. (see Progress in Flying Machines by Octave Chanute, pp. 142-143, Lorenz & Herweg 1894, reprinted 1976). The propeller and the wing are both formed with rigid leading edges and elastic posterior edges, and the propeller has practically no pitch except that imposed by the resultant air pressure upon the flexible trailing edge of the propeller during rotation. The overall shape of the wing is reminiscent of a butterfly, with outwardly convex posterior and anterior edges, and the wing material is specified as being mounted quite loosely upon the frame so as to undulate when under forward motion. The device is described as being quite erratic in flight, seldom pursuing the same course twice, rising to a maximum height of 20-30 feet and then gliding back down to the ground sustained by the wing alone. As a toy, this device is entertaining, providing an overall vertical, helicopter-like ascent followed by a glide to the ground in the manner of an airplane or glider. It is also apparent that such a toy has considerable educational value, in that it illustrates a wide variety of physical and aerodynamic principles in action.
However, this device was reported as providing less than ideal performance with an erratic flight path and a rather limited vertical range. What is needed is a device that preserves the simplicity and affordability of this design but offers stable aerodynamic performance in both the vertical ascent and the gliding descent flight regimes. Such a device would preferably be formed from lightweight, inexpensive materials that are easy and safe to work with, thus lending themselves to use in the classroom.